Multiplying a 2-digit number by
202
and
adding 11

Select a 2-digit number less than 50.

The result is:
First two digits of the product are two times the number selected.
Last two digits are two times the number.
Add 11.

Example:

Number selected is 21.
202 × 21 + 11
First two digits of the product are two times the selected number: 2(21) = 42.
Last two digits are two times the number: 2(21) = 42.
Add 11: 4242 + 11 = 4253.
So 202 times 21 plus 11 is 4253.

Example:

Number selected is 46.
202 × 46 + 11
First two digits of the product are two times the selected number: 2(46) = 92.
Last two digits are two times the number: 92.
Add 11: 9292 + 11 = 9303.
So 202 times 46 plus 11 is 9303.